Question

Modulus of rigidity of ideal liquids is

• A. infinity
• B. zero
• C. unity
• D. some finite small non - zero

Answer 1

The correct option is B

zero

Modulus of rigidity

Modulus of rigidity also known as Shear modulus is defined as the ratio of shear stress to the shear strain. S.I. unit for the modulus of rigidity is $N/m^2$ .

$Shearmodulus=\frac{ShearStress}{ShearStrain}$

In the case of ideal liquid, shear strain is $\infty$ and shear stress is the force F per unit area A.

Thus, $$\begin{gathered} Shearmodulus=\frac{F/A}{\infty } \\ Shearmodulus=0 \end{gathered}$$

Hence, the Modulus of rigidity of ideal liquids is 0.